Focus on learning instead of winning. Ask how you could have played better when winning or losing. Team mates may play a role in losses but don't get too focused on that.

Read your tooltips and practice on a training dummy. Class skills are more complicated than they appear and likely differ from their pve counterpart.

Work on situational awareness. You need to be thinking about positioning and where everyone is, who has LB on bothe enemy and ally side. Target and mark people with no mp who cannot heal.